[pixels-cache] reimplement shared-memory message queue.

[bianhq]

Currently, we are using the message queue implementation from MappedBus.
This message queue is backed by shared memory, but it is not a circular queue, which means it will stop working when the write pointer reaches the end of the shared memory.

We need to implement a circular message queue backed by shared memory. And the message queue should be safe for multiple threads or processes.

[bianhq]

Resolved.